CN111151743A - High-temperature die with graphite-low-temperature alloy-steel coupling heat transfer mode - Google Patents
High-temperature die with graphite-low-temperature alloy-steel coupling heat transfer mode Download PDFInfo
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- 238000012546 transfer Methods 0.000 title claims abstract description 20
- 229910000851 Alloy steel Inorganic materials 0.000 title claims abstract description 19
- 230000008878 coupling Effects 0.000 title abstract description 9
- 238000010168 coupling process Methods 0.000 title abstract description 9
- 238000005859 coupling reaction Methods 0.000 title abstract description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 133
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 132
- 239000010439 graphite Substances 0.000 claims abstract description 132
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 68
- 239000010959 steel Substances 0.000 claims abstract description 68
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 57
- 239000000956 alloy Substances 0.000 claims abstract description 57
- 238000004519 manufacturing process Methods 0.000 claims abstract description 33
- 238000004321 preservation Methods 0.000 claims abstract description 22
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 11
- 238000009529 body temperature measurement Methods 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 4
- 229910000634 wood's metal Inorganic materials 0.000 claims description 2
- 230000003647 oxidation Effects 0.000 abstract description 28
- 238000007254 oxidation reaction Methods 0.000 abstract description 28
- 238000010438 heat treatment Methods 0.000 abstract description 19
- 239000007788 liquid Substances 0.000 abstract description 17
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 13
- 229910052760 oxygen Inorganic materials 0.000 abstract description 13
- 239000001301 oxygen Substances 0.000 abstract description 13
- 238000000034 method Methods 0.000 abstract description 12
- 238000001816 cooling Methods 0.000 abstract description 10
- 230000008569 process Effects 0.000 abstract description 10
- 230000002035 prolonged effect Effects 0.000 abstract description 5
- 238000003754 machining Methods 0.000 abstract description 4
- 238000009413 insulation Methods 0.000 description 32
- 238000002844 melting Methods 0.000 description 23
- 230000008018 melting Effects 0.000 description 23
- 210000004379 membrane Anatomy 0.000 description 9
- 239000012528 membrane Substances 0.000 description 9
- 229910003460 diamond Inorganic materials 0.000 description 5
- 239000010432 diamond Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 4
- 210000002469 basement membrane Anatomy 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000011049 filling Methods 0.000 description 3
- 229920000742 Cotton Polymers 0.000 description 2
- 230000004308 accommodation Effects 0.000 description 2
- 239000010425 asbestos Substances 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011810 insulating material Substances 0.000 description 2
- 238000000053 physical method Methods 0.000 description 2
- 229910052895 riebeckite Inorganic materials 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004512 die casting Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/003—Apparatus, e.g. furnaces
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
The invention discloses a high-temperature die in a graphite-low-temperature alloy-steel coupling heat transfer mode, which belongs to the field of die manufacturing, and comprises a part manufacturing system and a heat preservation system, wherein the part manufacturing system comprises a graphite die, a low-melting-point alloy, a steel die sleeve and a bottom die, and the low-melting-point alloy is filled in an annular space between the graphite die and the steel die sleeve; the low-melting-point alloy wraps the outer surface of the graphite mold, so that the graphite mold is isolated from oxygen, the high-temperature oxidation resistance of the graphite mold is improved, the oxidation speed of the graphite mold is reduced, and the service life of the graphite mold is prolonged; the liquid low-melting-point alloy after heating provides a variable space for the expansion and deformation of the steel die sleeve and the graphite die, and the cooling shrinkage process is the same as the heating process before the low-melting-point alloy is solidified. The heat preservation system suit is in the outside of part manufacturing system, keeps warm to part manufacturing system, reduces thermal loss, improves energy utilization, reduces the power consumption, reduces parts machining cost.
Description
Technical Field
The invention belongs to the field of mold manufacturing, and particularly relates to a high-temperature mold in a graphite-low-temperature alloy-steel coupling heat transfer mode.
Background
With the development of modern industrial technology, the mold has irreplaceable role in the machining of the parts, especially in various machining and forming technologies, such as: the hot-press forming, the die-casting forming, the extrusion forming and the like all need the auxiliary forming of the die. Graphite has become a special industrial material because of its good electrical conductivity, thermal conductivity, self-wetting and high mechanical strength for wide industrial applications. However, graphite is very easy to oxidize at high temperature, and the oxidation starts from 450 ℃, and the oxidation is aggravated at 750 ℃, so that the oxidation corrosion is extremely accelerated. The sintering temperature for manufacturing the diamond drill is 950-1100 ℃, so that the graphite mold for manufacturing the drill is easy to oxidize, the mechanical properties of the graphite mold after oxidation are weakened, and the service life is greatly reduced.
At present, the service life of the graphite mold is prolonged by improving the oxidation resistance of the graphite mold, and the graphite mold is widely researched in the industry. Such as: zhangjiaquine et al propose to improve its oxidation resistance by changing the content of graphite and adding other elements. The content of the mould material is calculated by weight percentage, the mould material comprises 15-25% of asphalt, 3-5% of silicon nitride, 0.3-0.8% of titanium nitride, 0.1-0.5% of yttrium and 0.1-0.5% of erbium; the balance being graphite. The graphite is kneaded in a kneader and finally formed, and the method improves the oxidation resistance of the graphite by changing the original graphite structure. In addition, the service life of the graphite is prolonged through a physical method, and the long-life hollow graphite mold comprises a base, an outer membrane and an inner membrane, wherein the inner membrane is sleeved inside the outer membrane, the lower parts of the inner membrane and the outer membrane are connected with the upper part of the base which is integrally formed, cover plates are arranged above the inner membrane and the outer membrane, the outer side of the outer membrane is respectively wrapped with a first protection plate and a second protection plate, the first protection plate and the second protection plate are fixedly connected with a protection device, and the protection device is provided with a loop bar, a sleeve, a spring and the. The die mainly comprises an inner film and an outer film, wherein silicon carbide films are plated on the outer side of the inner film and the inner side of the outer film, and the service life of the die is prolonged by utilizing the high-temperature and oxidation resistance of the silicon carbide films.
The essence of the two methods is that the graphite material is blocked from contacting oxygen in the air at high temperature, complex manufacturing processes are respectively adopted, and the manufacturing cost is relatively high. Therefore, how to realize the isolation of the graphite mold from oxygen at high temperature by adopting a simple manufacturing process is a problem to be solved urgently.
Disclosure of Invention
Aiming at the problems that a graphite mold is easy to oxidize at high temperature and short in service life, the invention aims to provide the high-temperature mold in the graphite-low-temperature alloy-steel coupling heat transfer mode, so that the contact between the outer diameter surface of graphite and oxygen in air is blocked, the oxidation speed of a graphite layer on the outer surface of the graphite mold is reduced, even the graphite layer does not fall off, the graphite mold can be recycled, and the production cost of the mold is reduced.
The technical scheme adopted by the invention for realizing the purpose is as follows: a high temperature die of a graphite-low temperature alloy-steel coupled heat transfer mode, comprising: the part manufacturing system comprises a graphite die, a low-melting-point alloy, a steel die sleeve and a bottom die, wherein the graphite die is arranged inside the steel die sleeve and is coaxial with the steel die sleeve, an annular space is formed between the outer wall of the graphite die and the inner wall of the steel die sleeve, and the upper parts of the outer wall of the graphite die and the inner wall of the steel die sleeve are inclined surfaces which are inclined outwards gradually from bottom to top to form a dovetail groove type accommodating space which is wide at the top and narrow at the bottom; wherein the lower part of the inner wall of the steel die sleeve is radially and inwardly protruded to form an annular bulge, the lower part of the outer wall of the graphite die is of a stepped structure, and the stepped surface of the stepped structure is abutted against the annular bulge; the inner wall of the bottom die is in threaded connection with the lower part of the outer wall of the graphite die, the outer wall of the bottom die is in threaded connection with the annular bulge of the steel die sleeve, and a bottom die screwing and disassembling hole is formed in the bottom die; the low-melting-point alloy is filled in an annular space between the graphite die and the steel die sleeve; the heat preservation system suit is in the outside of part manufacturing system, the heat preservation system is including high temperature resistant insulation cover, high temperature resistant insulation cover and high temperature resistant insulation backing plate, high temperature resistant insulation cover is the open hollow structure in both ends from top to bottom, infrared ray temperature measurement hole has been seted up on high temperature resistant insulation cover's the lateral wall, infrared ray temperature measurement hole is the through hole, the upper portion opening detachably of high temperature resistant insulation cover is provided with high temperature resistant insulation cover, the lower part opening detachably of high temperature resistant insulation cover is provided with high temperature resistant insulation backing plate, high temperature resistant insulation cover and high temperature resistant insulation backing plate all with high temperature resistant insulation cover sealing connection.
Further, the inclined plane has an inclination angle of 300-600And the height is 3mm-30 mm.
In a preferred embodiment of the present invention, the inclined surface has an inclination angle of 450And a height of 10 mm.
Preferably, the low melting point alloy is wood's metal or tin.
Further, the temperature resistance of the steel die sleeve is at least 100 ℃ higher than the temperature required by a sample to be sintered.
Further, the diameter of the bottom die is at least 3mm smaller than that of the graphite die.
Through the design scheme, the invention can bring the following beneficial effects: the invention provides a high-temperature die in a graphite-low-temperature alloy-steel coupling heat transfer mode, which improves the original graphite die, and adds a low-melting-point alloy, a steel die sleeve and a heat preservation system, so that the outer surface of the graphite die is not contacted with oxygen in the air, the oxidation resistance of the graphite die is improved, the oxidation speed of the graphite die is reduced, the heat loss of a part manufacturing system is reduced by the heat preservation system, the energy utilization rate is improved, and the part manufacturing cost is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention to the right, and in which:
FIG. 1 is a schematic axial cross-sectional view of a high temperature mold of a graphite-low temperature alloy-steel coupled heat transfer mode according to an embodiment of the present invention;
FIG. 2 is a schematic axial section of a high-temperature die with a graphite-low-temperature alloy-steel coupled heat transfer mode along an infrared temperature measuring hole according to an embodiment of the invention.
The respective symbols in the figure are as follows: 1-a graphite mold; 2-low melting point alloy; 3-a steel die sleeve; 4-bottom die; 5-high temperature resistant heat preservation cover; 6-high temperature resistant insulating sleeve; 7-high temperature resistant heat preservation backing plate; 8-infrared thermometric hole; and 9-screwing and disassembling holes on the bottom die.
Detailed Description
In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. As will be appreciated by those skilled in the art. The following detailed description is illustrative rather than limiting in nature and is not intended to limit the scope of the invention.
As shown in figures 1 and 2, the graphite-low temperature alloy-steel coupled heat transfer mode high-temperature die provided by the invention adopts a physical method to improve the graphiteThe high temperature oxidation resistance of mould 1 reduces graphite mold 1's high temperature oxidation speed, the mould includes part preparation system and heat preservation system, and part preparation system is responsible for high temperature preparation part, and the heat preservation system is responsible for keeping warm, prevents calorific loss, reduces heating time, reduces the power consumption, reduces the parts machining cost. Part manufacturing system includes graphite mould 1, low melting point alloy 2, steel die sleeve 3 and die block 4, graphite mould 1 coaxial setting is in the inside of steel die sleeve 3, the annular space has between graphite mould 1's outer wall and steel die sleeve 3's the inner wall, and graphite mould 1's outer wall upper portion and steel die sleeve 3's inner wall upper portion are the inclined plane that leans out gradually from the bottom up, form narrow forked tail cell type accommodation space under the wide width, the angle of inclination on inclined plane is 300-600Between 3mm and 30mm in height, preferably with an angle of inclination of 450The height of the graphite mold is 10mm, wherein the lower part of the inner wall of the steel mold sleeve 3 protrudes inwards along the radial direction to form an annular bulge, the lower part of the outer wall of the graphite mold 1 is of a stepped structure, and the stepped surface of the stepped structure is abutted against the annular bulge; the inner wall of the bottom die 4 is in threaded connection with the lower part of the outer wall of the graphite die 1, the outer wall of the bottom die 4 is in threaded connection with the annular bulge of the steel die sleeve 3, and a bottom die screwing and disassembling hole 9 is formed in the bottom die 4 and used for conveniently screwing and disassembling the bottom die 4; the low melting point alloy 2 is filled in the annular space between the graphite mold 1 and the steel mold 3. The heat preservation system suit is in the outside of part manufacturing system, the heat preservation system is including high temperature resistant insulation cover 5, high temperature resistant insulation cover 6 and high temperature resistant insulation backing plate 7, high temperature resistant insulation cover 6 is the open hollow structure in upper and lower both ends, infrared ray temperature measurement hole 8 has been seted up on the lateral wall of high temperature resistant insulation cover 6, infrared ray temperature measurement hole 8 is the through hole, the upper portion opening detachably of high temperature resistant insulation cover 6 is provided with high temperature resistant insulation cover 5, the lower part opening detachably of high temperature resistant insulation cover 6 is provided with high temperature resistant insulation backing plate 7, high temperature resistant insulation cover 5 and high temperature resistant insulation backing plate 7 all with high temperature resistant insulation cover 6 sealing connection, high temperature resistant insulation cover 5 and high temperature resistant insulation backing plate 7 are sealed high temperature resistant insulation cover 6 from top to bottom.
Wherein the material and volume of the low melting point alloy 2 are determined by the heating temperature of the sample to be sintered, the expansion coefficients of the steel die sleeve 3 and the graphite die 1, and the steel dieThe annular space between the sleeve 3 and the graphite mould 1 is determined jointly, for example wood's alloy, tin, etc. The low-melting-point alloy 2 is filled between the graphite die 1 and the steel die sleeve 3, and the low-melting-point alloy 2 is a material with low melting point, high boiling point, good heat conductivity and small thermal expansion coefficient. The effect of filling the low-melting-point alloy 2 in the annular space between the graphite mold 1 and the steel mold 3 is as follows: first, the thermal expansion coefficient of graphite is 1.6X 10-6The coefficient of thermal expansion of steel is 1.2X 10 DEG C-5The difference of the thermal expansion coefficients of graphite and steel is large, if the graphite die 1 and the steel die sleeve 3 are directly nested and matched for seamless connection, the steel and the graphite expand simultaneously when the manufactured parts are heated, and contract after cooling. Therefore, a contraction gap is reserved between the graphite die 1 and the steel die sleeve 3, air can be generated through the gap, and the graphite can be oxidized as long as the graphite is in contact with the air, so that the contraction gap is filled with the low-melting-point alloy 2. The low melting point alloy 2 is firstly melted at a lower temperature (about 200 ℃), the expansion speed of graphite and steel is low at the temperature, the expansion amount is small, and the low melting point alloy 2 is changed into a liquid state after being melted so as to provide a variable space for the expansion, cooling shrinkage and deformation of the graphite and the steel; secondly, the low-melting-point alloy 2 has good thermal conductivity, so that the heated heat can be transferred to the graphite mold 1, and the heat loss in the heat transfer process is reduced; thirdly, the steel die sleeve 3 and the low melting point alloy 2 can prolong the service life of the graphite die 1, but when the service life of the graphite die 1 is ended, the low melting point alloy 2 can be heated and melted and then taken out of the graphite die 1 when the graphite die can not be used any more, and the low melting point alloy 2 can facilitate the replacement of the graphite die 1; fourthly, basement membrane 4 adopts threaded connection with steel die sleeve 3, and basement membrane 4 is located graphite jig 1 below simultaneously, and basement membrane 4 adopts threaded connection with graphite jig 1, and threaded connection makes graphite jig 1, steel die sleeve 3 and die block 4 concentricity relatively poor, and the poor shortcoming of concentricity has been remedied in the existence of low melting point alloy 2.
Wherein, the material of the steel die sleeve 3 is determined according to the temperature of the sample to be sintered, and the size of the steel die sleeve 3 is determined according to the size of the graphite die 1. The temperature resistance of the steel die sleeve 3 is at least 100 ℃ higher than the temperature required by a sample to be sintered.
The bottom die 4 is determined according to the size of the graphite die 1, the diameter of the bottom die 4 is at least 3mm smaller than that of the graphite die 1, so that the graphite die 1 and the steel die sleeve 3 are completely contacted to achieve the sealing degree, and the liquid low-melting-point alloy 2 cannot flow out from threads between the bottom die 4 and the steel die sleeve 3. The thickness of the bottom mold 4 is determined as the case may be.
The high-temperature-resistant heat-insulating cover 5, the high-temperature-resistant heat-insulating sleeve 6 and the high-temperature-resistant heat-insulating base plate 7 are made of high-temperature-resistant insulating materials, such as asbestos and high-temperature-resistant insulating cotton, and have excellent heat-insulating property, high-temperature resistance, insulating property and plasticity. The heat preservation system suit is in the outside of part manufacturing system, with the fine parcel of part manufacturing system on, makes it prevent thermal dissipation when heating, improves heat utilization ratio, reduces thermal loss, reduces heating and heat preservation time. The infrared temperature measuring hole 8 on the high-temperature resistant heat insulation sleeve 6 can directly measure the temperature of the part manufacturing system through the infrared temperature measuring hole 8, the temperature of the part manufacturing system can be accurately controlled, and the success rate of part manufacturing is increased. The heat preservation system greatly reduces heat loss of the part manufacturing system, improves the energy utilization rate, reduces the heating cost and reduces the part manufacturing cost.
The high-temperature die in the graphite-low-temperature alloy-steel coupling heat transfer mode is heated by a high-frequency furnace (heating tool), after the graphite die 1 in a part manufacturing system is charged, the part manufacturing system is directly wrapped by a heat insulation system and placed into a coil in the high-frequency furnace, the coil vibrates, and the insulation of the heat insulation system enables the high-temperature die not to participate in the heating of the part manufacturing system and only plays a role in heat insulation.
The graphite mold 1 is externally wrapped by the low-melting-point alloy 2, the low-melting-point alloy 2 is in a liquid state after being heated, for example, when the diamond bit is manufactured and heated to 950-1100 ℃, the low-melting-point alloy 2 does not reach a boiling point, bubbles cannot be generated due to boiling, oxygen cannot be generated due to no bubbles, no oxygen directly contacts graphite, and the graphite mold 1 cannot be oxidized at high temperature or the oxidation speed of the graphite can be greatly reduced even if the graphite mold is oxidized. Low melting point alloy 2 can expand after heating high temperature melting, but the expanded volume is less, narrow forked tail cell type accommodation space under the last width that steel die sleeve 3 and graphite jig 1 upper portion formed, can hold low melting point alloy 2 that the inflation came out, can cool off the shaping certainly after the part heating preparation is accomplished, low melting point alloy 2 cooling shrinkage after the cooling, the low melting point alloy 2 that the inflation was left during cooling shrinkage also can contract the annular space clearance between the inner wall of filling graphite jig 1 and the outer wall of steel die sleeve 3. The change of the low-melting-point alloy 2 in the whole heating, heat preservation and cooling processes is a dynamic change process. Of course, the specific case is specifically analyzed as follows: when tin is selected as the low-melting-point alloy 2, the volume of the tin is determined according to the thermal expansion coefficient of the tin, the annular space between the steel die sleeve 3 and the graphite die 1 and the thermal expansion coefficients of the steel die sleeve 3 and the graphite die 1, so that the whole dovetail groove type accommodating space is just filled after the tin is heated to expand, the oxidation speed of the graphite at high temperature is known to be very high, so that the outer surface of the graphite die 1 is completely wrapped by the tin by just filling the whole dovetail groove type accommodating space with the tin after heating, oxygen is completely isolated, the high-temperature oxidation speed of the graphite is reduced, after the temperature is reduced, although the volume of the tin is shrunk, the height of the liquid tin is reduced very little, and the oxidation speed of the graphite die 1 is also reduced after the temperature is reduced. In conclusion, the existence of the low-melting-point alloy 2 isolates oxygen, reduces the oxidation speed of graphite and prolongs the service life of the outer surface of the graphite. The inner surface of the graphite mold 1 is in contact with a sample to be sintered, and the principle is consistent with the protection mechanism of the outer surface of the graphite mold 1 and the low-melting-point alloy 2.
The working principle is as follows:
the high-temperature die with the graphite-low-temperature alloy-steel coupling heat transfer mode provided by the invention has three working principles: firstly, adopt the contact of isolated graphite jig 1 of low melting point alloy 2 and oxygen, increase graphite high temperature oxidation resistance, reduce the oxidation rate of graphite, improve graphite jig 1's life. Secondly, the low-melting-point alloy 2 solves the problem that the steel die sleeve 3 is cooled, shrunk and fractured by the graphite die 1 due to the direct contact of the steel die sleeve 3 and the graphite die 1. The existence of low melting point alloy 2 provides variable space for the thermal expansion of steel die sleeve 3 and graphite mold 1, even if the thermal expansion coefficient difference is great, because steel die sleeve 3 and graphite mold 1 only can be heated to expand after the high temperature, low melting point alloy 2 presents liquid after the high temperature, liquid low melting point alloy 2 has mobility, makes steel die sleeve 3 and graphite mold 1 have the buffer space, has solved the fracturing problem of graphite mold 1 under the contractile force of steel die sleeve 3. And the heat preservation system is made of high-temperature-resistant insulating materials, such as asbestos and high-temperature-resistant insulating cotton, has good heat preservation performance, high temperature resistance, good insulativity and strong plasticity, can be randomly changed according to the shape of the part manufacturing system, reduces heat loss, increases the energy utilization rate and reduces the part manufacturing cost.
Referring to fig. 1 and 2, the working process of the high-temperature die in the graphite-low-temperature alloy-steel coupling heat transfer mode provided by the invention can be divided into three stages, wherein the first stage is a heating process, a steel die sleeve 3 and a graphite die 1 expand simultaneously in the heating process, at the moment, a low-melting-point alloy 2 melts in the heating process, the flowability of the liquid low-melting-point alloy 2 provides a variable space for the expansion of the steel die sleeve 3 and the graphite die 1, the expansion coefficient of the steel die sleeve 3 is large, the expansion coefficient of the graphite die 1 is small, the solid state of the low-melting-point alloy 2 is changed into the liquid state, the volume of the low-melting-point alloy 2 is increased, under the combined action of the three, the liquid level of the liquid low-melting-point alloy 2 rises or falls in a dovetail groove type accommodating space, and the liquid level changes according. The dovetail groove shape is wide at the top and narrow at the bottom so that the liquid level height of the low melting point alloy 2 in the liquid state does not change much. The liquid low-melting-point alloy 2 can well wrap the outer surface of the graphite mold 1 in the whole heating process, and can play a good role in isolating oxygen, so that the graphite is not easily oxidized at high temperature or the oxidation speed is reduced; the second stage is a heat preservation stage, a heat preservation process of a period of time is needed in the processing process of manufacturing parts such as diamond bits and the like, the process is the extreme point of the first stage, namely the heating process, at the moment, the states of the steel die sleeve 3, the graphite die 1, the low-melting-point alloy 2 and the like are not changed, and the stable state is kept; the third stage is a cooling stage, the cooling stage is the reverse process of the heating stage, the steel die sleeve 3 and the graphite die 1 start to shrink in the process of temperature reduction, but the steel die sleeve 3 generates a large shrinkage force at the moment when the shrinkage speed is different, but because the low-melting-point alloy 2 is still in a liquid state at the moment, a buffer space is provided for the steel die sleeve 3 and the graphite die 1, and the possibility that the graphite is fractured cannot occur. When the temperature is reduced to about 200 ℃, the low melting point alloy 2 starts to have liquid state to solid state, but the cooling shrinkage and deformation of the steel die sleeve 3 and the graphite die 1 are basically kept unchanged, so that the whole structure is basically not influenced. In conclusion, the graphite mold 1 is wrapped by the low-melting-point alloy 2 in the three stages, so that the graphite mold 1 is not contacted with oxygen, the oxidation speed is reduced, the high-temperature oxidation resistance is improved, and the service life of the graphite mold 1 is prolonged.
After a drill bit is manufactured by the traditional diamond drill bit graphite mold, the outer surface of the graphite mold is scrapped due to severe oxidation at high temperature, the outer surface of the graphite mold 1 is isolated from oxygen, the high-temperature oxidation resistance is improved, the oxidation speed at high temperature is reduced, the diamond drill bit can be continuously used after being manufactured, and the shape of the mold is basically unchanged. When the inner surface of the graphite mold 1 is oxidized to be incapable of being applied or the size of the graphite mold is not accurate enough, the graphite mold 1 can be damaged and detached by unscrewing the bottom mold 4, the steel mold sleeve 3 and the low-melting-point alloy 2 are continuously used, and a new graphite mold 1 is replaced.
The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention, the scope of the present invention is defined by the appended claims, and all structural changes that can be made by using the contents of the description and the drawings of the present invention are intended to be covered by the scope of the present invention.
Claims (6)
1. A high temperature die of a graphite-low temperature alloy-steel coupled heat transfer mode, comprising: the part manufacturing system comprises a graphite die (1), a low-melting-point alloy (2), a steel die sleeve (3) and a bottom die (4), wherein the graphite die (1) is arranged inside the steel die sleeve (3) and is coaxial with the steel die sleeve, an annular space is formed between the outer wall of the graphite die (1) and the inner wall of the steel die sleeve (3), and the upper part of the outer wall of the graphite die (1) and the upper part of the inner wall of the steel die sleeve (3) are inclined planes which are gradually inclined outwards from bottom to top to form a dovetail groove type accommodating space which is wide at the top and narrow at the bottom; wherein the lower part of the inner wall of the steel die sleeve (3) is radially and inwardly protruded to form an annular protrusion, the lower part of the outer wall of the graphite die (1) is of a stepped structure, and the stepped surface of the stepped structure is abutted against the annular protrusion; the inner wall of the bottom die (4) is in threaded connection with the lower part of the outer wall of the graphite die (1), the outer wall of the bottom die (4) is in threaded connection with the annular bulge of the steel die sleeve (3), and a bottom die screwing and disassembling hole (9) is formed in the bottom die (4); the low-melting-point alloy (2) is filled in an annular space between the graphite die (1) and the steel die sleeve (3); the heat preservation system suit is in the outside of part manufacturing system, the heat preservation system is including high temperature resistant insulating cover (5), high temperature resistant insulating cover (6) and high temperature resistant insulating backing plate (7), high temperature resistant insulating cover (6) are the open hollow structure in upper and lower both ends, infrared ray temperature measurement hole (8) have been seted up on the lateral wall of high temperature resistant insulating cover (6), infrared ray temperature measurement hole (8) are the through hole, the upper portion uncovered department detachably of high temperature resistant insulating cover (6) is provided with high temperature resistant insulating cover (5), the lower part uncovered department detachably of high temperature resistant insulating cover (6) is provided with high temperature resistant insulating backing plate (7), high temperature resistant insulating cover (5) and high temperature resistant insulating backing plate (7) all with high temperature resistant insulating cover (6) sealing connection.
2. The high temperature mold of graphite-low temperature alloy-steel coupled heat transfer mode of claim 1, wherein: the inclined surface has an inclination angle of 300-600And the height is 3mm-30 mm.
3. The high temperature mold of graphite-low temperature alloy-steel coupled heat transfer mode of claim 1, wherein: the inclined surface has an inclination angle of 450And a height of 10 mm.
4. The high temperature mold of graphite-low temperature alloy-steel coupled heat transfer mode of claim 1, wherein: the low-melting-point alloy (2) is wood's metal or tin.
5. The high temperature mold of graphite-low temperature alloy-steel coupled heat transfer mode of claim 1, wherein: the temperature resistance of the steel die sleeve (3) is at least 100 ℃ higher than the temperature required by a sample to be sintered.
6. The high temperature mold of graphite-low temperature alloy-steel coupled heat transfer mode of claim 1, wherein: the diameter of the bottom die (4) is at least 3mm smaller than that of the graphite die (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010114258.XA CN111151743B (en) | 2020-02-25 | High-temperature die with graphite-low-temperature alloy-steel coupling heat transfer mode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010114258.XA CN111151743B (en) | 2020-02-25 | High-temperature die with graphite-low-temperature alloy-steel coupling heat transfer mode |
Publications (2)
| Publication Number | Publication Date |
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| CN111151743A true CN111151743A (en) | 2020-05-15 |
| CN111151743B CN111151743B (en) | 2024-06-28 |
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